The present invention relates to a new and distinct cultivar of Heuchera and given the cultivar name of ‘TNHEUNEB’. Heuchera is in the family Saxifragaceae. Heuchera ‘TNHEUNEB’ originated from a controlled cross using Heuchera ‘K963-1’, a proprietary, unpatented, plant as the seed parent, and Heuchera ‘K991-2’, a proprietary, unpatented, plant as the pollen parent. These parents are a result of breeding using hardy Heuchera richardsonii with proprietary hybrid lines. Heuchera ‘TNHEUNEB’ was bred to be a hardy, large, landscape plant.
The trademark designation for the claimed plant is Northern Exposure™ Black.
Compared to the seed parent, Heuchera ‘K963-1’, the new cultivar has larger, blacker leaves, and a larger habit.
Compared to the pollen parent, Heuchera ‘K991-2’, the new cultivar has a larger habit and shinier black leaves.
Compared to Heuchera ‘Obsidian’, U.S. Plant Pat. No. 14,836, the new cultivar has larger, rounder leaves and a bigger habit.
Compared to Heuchera ‘Blackout’, U.S. Plant Pat. No. 20,613, the new cultivar has larger leaves with more rounded leaf lobes, and a bigger habit.
This new Heuchera is uniquely distinguished by:                1. brown-black to black colored leaves,        2. medium large, geranium-like leaves with shallow rounded lobes,        3. very light pink flowers on upright flowering stems,        4. good cold and sun tolerance,        5. a large, mounding habit with an excellent crown count, and        6. excellent vigor.        
This new cultivar has been reproduced only by asexual propagation (tip cuttings and tissue culture using growing tips). Each of the progeny exhibits identical characteristics to the original plant. Asexual propagation by cuttings and tissue culture using standard micropropagation techniques with terminal and lateral shoots, as done in Canby, Oreg., shows that the foregoing characteristics and distinctions come true to form and are established and transmitted through succeeding propagations. The present invention has not been evaluated under all possible environmental conditions. The phenotype may change with variations in environment without a change in the genotype of the plant.